1. Field of the Invention
The present invention relates to signal processing using a moving picture experts group (MPEG) standard etc., and more particularly, to an apparatus and method for processing a multi-channel audio signal using space information.
2. Description of Related Art
In a conventional method and apparatus for processing an audio signal, spatial audio coding (SAC) for restoring surround components only using binaural cue coding (BCC) is used when restoring a multi-channel audio signal. SAC is disclosed in the paper “High-quality Parametric Spatial Audio Coding at Low Bitrates,” 116th AES convention, Preprint, p. 6072, and BCC is disclosed in the paper “Binaural Cue Coding Applied to Stereo and Multi-Channel Audio Compression,” 112th AES convention, Preprint, p. 5574.
In the above conventional method using SAC, surround components disappear when a stereo signal is down-mixed. In other words, a down-mixed stereo signal does not include the surround components. Thus, since side information having a large amount of data should be transmitted to restore the surround components when restoring a multi-channel audio signal, the conventional method has the drawback of a low channel transmission efficiency. Further, since the disappeared surround components are restored, the sound quality of the restored multi-channel audio signal is degraded.